VintageVmax.com

Hello all newbe to your forum. my 83 vmax ruined a piston. the clutch side cylinder looks like its going to need to be bored.not a big deal im going to put in wiseco pistons (if available) i will bore both jugs the same.i will replace the crank seals inspect the bearings. the issue i have is it appeares that the cylinders are not plated? i was told by a local yamaha guru that they were not plated till the middle 1990's is this true? also one cylinder has a iron sleeve and the other is just the aluminum bore. i dont think this will be an issue as long as i use the proper rings in each bore. has anyone any info saying these cylinders need to be plated? i plan on boring it .020 to .040 overbore. is there anything to look for when i have this motor apart? it has 2,600 miles on the machine.i expect it to be in pretty good shape down below.

As far as i know all cylinders were plated. I have a 85 vmax and just had them re-plated as im sure you know you cant bore plated cylinders. When i had my motor apart i just checked the crank,inspected the bottom end,cleaned the carbs really good,put all new oil and fuel lines on. If i were you i would get cylinders that are plated or cast i would not have one of each on my sled,if i did mine over i would go with cast just for the ease of boring. To re-plate mine it was 175 per cylinder.

Brjr540 Welcome to V.V. ! Yes, the stock cylinders were Chrome. You can either have them replated with nikasil plating or resleeved with cast iron sleeves which allow overbore. Make sure both bores are the same size and material.



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hello again. i have found several sites that sell pistons for the 540 engine.. are the pistons diffrent in the vmax vs the xl-v the srv 540 or the vk 540? i know these are air cooled are the pistons interchangeable?

brjr540 wrote:hello again. i have found several sites that sell pistons for the 540 engine.. are the pistons diffrent in the vmax vs the xl-v the srv 540 or the vk 540? i know these are air cooled are the pistons interchangeable?

No the Air cooled sleds do Not share the same pistons with the Vmax 540. PS. check out my Inventory/parts list for items I have for sale. Later Chuck

you might have to keep the stock bore, my parts guy called wiseco and they told him all oversize vmax pistons are discontinued, he said wiseco was the last to make oversize pistons

F.Y.I.

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well after an exhausting search for parts and information i got my 83 vmax done. i located a complete used engine assembly(minus carbs at my local snowmobile salvage and parts. that engine had one jug with an iron sleeve so i took then to my local cylinder boring specialists and a couple days later installed them with my new pistons and am ready to run... my machine has th 44mm mikuni carbs and they were jetted WAY too lean i went to a 300 mains and 132 on the power jets. this thing was jetted for 60 deg weather. and whoever worked on it before.. shame on them. they shouldnt be allowed to work on anything more complex than a walking stick. thanks again everyone for all the great info and tips to get me back on the trail...

I would use a set of EGT gauges if you can find them. Just for reference, I am at 350 mains on my 38 mm carbs because the midrange was very lean. 1275 deg crusing but the PJ's did fatten it up some on the top end. I will say, mine is ported and I run without the air box, but your carbs flow alot more air then mine. Be safe, start rich